This paper presents a novel 10 GHz bio-radar system based on a frequency multiplier and phase-locked loop (PLL) for non-contact measurement of heartbeat and respiration rates. In this paper, a 2.5 GHz voltage controlled oscillator (VCO) with PLL is employed as a frequency synthesizer, and 10 GHz continuous wave (CW) signal is generated by using frequency multiplier from 2.5 GHz signal. This paper also presents the noise characteristics of the proposed system, and the analysis result shows that the same signal-to-noise-ratio (SNR) performance can be achieved with the proposed system based on the frequency multiplier compared with the conventional system with identical carrier frequency. The experimental results shows excellent vital-signal measurement up to 100 cm without any additional digital signal processing (DSP), thus proving the validity of the proposed system.
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